Antistatic agent for thermoplastic resin

ABSTRACT

An antistatic agent for thermoplastic resins (Z) containing a block polymer (A) having a block of a hydrophobic polymer (a) and a block of a hydrophilic polymer (b) as structure units, and a C6-C18 branched alkylbenzenesulfonate (S); an antistatic resin composition (Y) containing the antistatic agent (Z) and a thermoplastic resin (E); and a molded article of the antistatic resin composition (Y).

TECHNICAL FIELD

The present invention relates to an antistatic agent for thermoplasticresins, an antistatic resin composition, and a molded article.

BACKGROUND ART

Conventionally, an antistatic agent has been commonly used as a methodof imparting antistatic property to highly insulating thermoplasticresins. Methods of imparting antistatic property using an antistaticagent include a known method in which a small amount of polyether esteramide serving as a polymer antistatic agent (for example, see PatentLiterature 1) is kneaded into a resin.

However, the antistatic property imparted by the method of kneading thepolymer antistatic agent is considered to be insufficient.

CITATION LIST Patent Literature

-   Patent Literature 1: JP H08-12755 A

SUMMARY OF INVENTION Technical Problem

An object of the present invention is to provide an antistatic agent forthermoplastic resins, which imparts excellent antistatic property tomolded articles containing a thermoplastic resin.

Solution to Problem

As a result of extensive studies to achieve the object, the presentinventors arrived at the present invention. Specifically, the presentinvention provides an antistatic agent for thermoplastic resins (Z)containing a block polymer (A) having a block of a hydrophobic polymer(a) and a block of a hydrophilic polymer (b) as structure units, and aC6-C18 branched alkylbenzenesulfonate (S). The present invention alsoprovides an antistatic resin composition (Y) containing the antistaticagent for thermoplastic resins (Z) and a thermoplastic resin (E). Thepresent invention still also provides a molded article of the antistaticresin composition (Y).

Advantageous Effects of Invention

The present invention can improve the continuous moldability(demoldability) during molding and can provide molded articles excellentin antistatic property and mechanical strength (mechanical properties).

DESCRIPTION OF EMBODIMENTS

An antistatic agent for thermoplastic resins (Z) of the presentinvention contains a block polymer (A) having a block of a hydrophobicpolymer (a) and a block of a hydrophilic polymer (b) as structure units,and a C6-C18 branched alkylbenzenesulfonate (S).

<Hydrophobic Polymer (a)>

Preferably, the hydrophobic polymer (a) in the present invention is atleast one selected from the group consisting of a polyamide (a1), apolyolefin (a2), and a polyester (a3).

The hydrophobic polymer (a) is more preferably the polyamide (a1) or thepolyolefin (a2), particularly preferably the polyolefin (a2) in terms ofantistatic property.

Preferably, the hydrophobic polymer (a) in the present invention is apolymer having a volume specific resistance greater than 1×10¹¹ Ω·cm.

The volume specific resistance in the present invention is a numericalvalue determined under an atmospheric environment at 23° C. with 50% RHaccording to ASTM D257 (1984).

The hydrophobic polymer (a) may consist of one of the above hydrophobicpolymers or a combination of two or more of those.

<Polyamide (a1)>

Examples of the polyamide (a1) in the present invention include thoseobtained by ring-opening polymerization or polycondensation of anamide-forming monomer (a10).

Examples of the amide-forming monomer (a10) include a lactam (a101) andan aminocarboxylic acid (a102). The amide-forming monomer (a10) may be acombination of a diamine (a103) and a dicarboxylic acid (a104).

Specifically, examples of the polyamide (a1) include those obtained byring-opening polymerization or polycondensation of the lactam (a101) orthe aminocarboxylic acid (a102) and a polycondensate of the diamine(a103) and the dicarboxylic acid (a104).

Examples of the lactam (a101) include lactams having 4 to 20 carbonatoms (hereinafter, the number of carbon atoms may be abbreviated as C)(e.g., γ-lactam, δ-lactam, ε-caprolactam, enantholactam, capryliclactam, ω-laurolactam, and undecanolactam).

Examples of ring-opening polymers of the lactam (a101) include nylon 4,nylon 5, nylon 6, nylon 7, nylon 8, nylon 11, and nylon 12.

Examples of the aminocarboxylic acid (a102) include C6-C12aminocarboxylic acids (e.g., ω-aminocaproic acid, ω-aminoenanthic acid,ω-aminocaprylic acid, ω-aminopelargonic acid, ω-aminocapric acid,11-aminoundecanoic acid, 12-aminododecanoic acid, and mixtures ofthese).

Examples of the diamine (a103) include C2-C40 diamines, such asaliphatic, alicyclic, or aromatic diamines, aromatic aliphatic diamines,and mixtures of these.

Examples of the aliphatic diamines include C2-C40 aliphatic diamines(e.g., ethylenediamine, propylenediamine, hexamethylenediamine,decamethylenediamine, 1,12-dodecanediamine, 1,18-octadecanediamine, and1,20-eicosanediamine).

Examples of the alicyclic diamine include C5-C40 alicyclic diamines(e.g., 1,3- or 1,4-cyclohexanediamine, isophoronediamine,4,4′-diaminocyclohexylmethane, and 2,2-bis(4-aminocyclohexyl)propane).

Examples of the aromatic diamines include C6-C40 aromatic diamines(e.g., p-phenylenediamine, 2,4- or 2,6-toluenediamine, and2,2-bis(4,4′-diaminophenyl)propane).

Examples of the aromatic aliphatic diamines include C7-C20 aromaticaliphatic diamines (e.g., xylylenediamine, bis(aminoethyl)benzene,bis(aminopropyl)benzene, and bis(aminobutyl)benzene).

Examples of the dicarboxylic acid (a104) include C2-C40 dicarboxylicacids. Examples include aliphatic dicarboxylic acids; aromaticring-containing dicarboxylic acids; alicyclic dicarboxylic acids;derivatives of these dicarboxylic acids, such as acid anhydrides, lower(C1-C4) alkyl esters, and dicarboxylic acid salts (e.g., alkali metalsalts, such as lithium, sodium, and potassium salts); and mixtures oftwo or more of these.

Examples of the aliphatic dicarboxylic acids include C2-C40 (preferablyC4-C20, more preferably C6-C12 in terms of antistatic property)aliphatic dicarboxylic acids (e.g., succinic acid, glutaric acid, adipicacid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanediacid, dodecane diacid, maleic acid, fumaric acid, and itaconic acid).

Examples of the aromatic ring-containing dicarboxylic acids includeC8-C40 (preferably C8-C16, more preferably C8-C14 in terms of antistaticproperty) aromatic ring-containing dicarboxylic acids (e.g.,orthophthalic acid, isophthalic acid, terephthalic acid, 2,6- or2,7-naphthalenedicarboxylic acid, diphenyl-4,4′-dicarboxylic acid,diphenoxyethanedicarboxylic acid, toluenedicarboxylic acid,xylylenedicarboxylic acid, and 5-sulfoisophthalic acid alkali metal (asdescribed above) salts).

Examples of the alicyclic dicarboxylic acids include C5-C40 (preferablyC6-C18, more preferably C8-C14 in terms of antistatic property)alicyclic dicarboxylic acids (e.g., cyclopropanedicarboxylic acid,1,4-cyclohexanedicarboxylic acid, cyclohexenedicarboxylic acid,dicyclohexyl-4,4′-dicarboxylic acid, and camphoric acid).

The amide-forming monomer (a10) is preferably ε-caprolactam,12-aminododecanoic acid, or a combination of adipic acid andhexamethylenediamine in terms of antistatic property.

The polyamide (a1) may be produced by a method in which theamide-forming monomer (a10) is ring-opening polymerized or polycondensedin the presence of a molecular weight adjusting agent. The molecularweight adjusting agent may be either a diamine or a dicarboxylic acid.Examples of the diamine and the dicarboxylic acid include compoundsmentioned as examples of the diamine (a103) (C2-C40, preferably C4-C20)and the dicarboxylic acid (a104) (C2-C40, preferably C4-C20),respectively. One of these compounds may be used alone, or two or moreof these may be used.

The amount of the molecular weight adjusting agent used is preferably 2to 80 wt %, more preferably 4 to 75 wt % based on the total weight ofthe amide-forming monomer (a10) and the molecular weight adjusting agentin terms of antistatic property.

The number average molecular weight of the polyamide (a1) is preferably200 to 5,000, more preferably 500 to 4,000, particularly preferably 800to 3,000 in terms of antistatic property and moldability.

Herein, the number average molecular weight of the polymer (hereinafterabbreviated as Mn) is a value measured by gel permeation chromatography(GPC) under the following conditions.

Device: “HLC-8120” (available from Tosoh Corporation)

Column: “TSK gel GMHXL” (available from Tosoh Corporation) (two columns)and “TSK gel Multipore HXL-M” (available from Tosoh Corporation) (onecolumn)

Sample solution: 0.3 wt % ortho dichlorobenzene solution

Amount of solution added: 100 μl

Flow rate: 1 ml/min

Measurement temperature: 135° C.

Detecting device: refractive index detector

Reference material: standard polystyrene (TSK standard POLYSTYRENE) 12samples (molecular weight: 500, 1,050, 2,800, 5,970, 9,100, 18,100,37,900, 96,400, 190,000, 355,000, 1,090,000, 2,890,000) (available fromTosoh Corporation)

<Polyolefin (a2)>

Preferably, the polyolefin (a2) in the present invention is a polyolefinhaving a reactive group. Examples of the polyolefin (a2) include apolyolefin (a21) having a reactive group at each end and a polyolefin(a22) having a reactive group at one end.

The reactive group refers to a carboxy group, a carboxylic acidanhydride group, a hydroxy group, an amino group, and an isocyanategroup.

<Polyolefin (a21) Having a Reactive Group at Each End>

Examples of the polyolefin (a21) having a reactive group at each endinclude a polyolefin (a21-1) having a carboxy group or a carboxylic acidanhydride group at each end of the polymer, a polyolefin (a21-2) havinga hydroxy group at each end of the polymer, a polyolefin (a21-3) havingan amino group at each end of the polymer, and a polyolefin (a21-4)having an isocyanate group at each end of the polymer. Of these, thepolyolefin (a21-1) having a carboxy group or a carboxylic acid anhydridegroup at each end of the polymer is preferred in terms of ease ofmodification and heat resistance during molding.

The “end” herein refers to a terminal portion where the repeatedstructure of the monomer unit constituting the polymer terminates. The“each end” refers to each end of the main chain of the polymer.

The polyolefin (a21) having a reactive group at each end can be obtainedby, for example, introducing a carboxy group, a carboxylic acidanhydride group, a hydroxy group, an amino group, or an isocyanate groupinto each end of a polyolefin (a21-0) mainly containing a polyolefin inwhich each end is modifiable.

The “mainly containing” herein means that the weight of the polyolefinin which each end is modifiable accounts for 50 wt % or more of theweight of the whole polyolefin.

However, even when the weight of the polyolefin in which each end ismodifiable accounts for less than 50 wt % of the weight of the wholepolyolefin, if the total weight of the polyolefin in which each end ismodifiable and a polyolefin in which one end is modifiable describedlater accounts for 50 wt % or more of the weight of the wholepolyolefin, and the weight of the polyolefin in which each end ismodifiable is greater than the weight of the polyolefin in which one endis modifiable, such a polyolefin is considered to be the polyolefin(a21-0) mainly containing a polyolefin in which each end is modifiable.

Examples of the polyolefin (a21-0) mainly containing a polyolefin inwhich each end is modifiable include a polyolefin obtained by(co)polymerization of one of C2-C30 (preferably C2-C12, more preferablyC2-C10) olefins or a mixture of two or more thereof and containing 30mol % or more of a propylene-derived structure unit, and a degradedpolyolefin (obtained by mechanically, thermally, or chemically degradinga high-molecular-weight (preferably, the Mn is 10,000 to 150,000)polyolefin). The “(co)polymerization” refers to polymerization orcopolymerization.

Of these, a degraded polyolefin is preferred, and a thermally degradedpolyolefin is more preferred in terms of ease of modification uponintroduction of a carboxy group, a carboxylic acid anhydride group, ahydroxy group, an amino group, or an isocyanate group, and easyavailability. Thermal degradation easily provides a low-molecular-weightpolyolefin in which the number of terminal double bonds per molecule isone or two as described later, and the low-molecular-weight polyolefinis easily modifiable by introduction of a carboxyl group, a carboxylicanhydride group, a hydroxyl group, an amino group, or an isocyanategroup.

Examples of the thermally degraded polyolefin include one obtained byheating a high-molecular-weight polyolefin in an inert gas (one obtainedby heating at 300° C. to 450° C. for 0.5 to 10 hours, for example, bythe method described in JP H03-62804 A) and one obtained by thermaldegradation by heating in the air.

Examples of the high-molecular-weight polyolefin used in thermaldegradation include a (co)polymer of a mixture of one or more of C2-C30(preferably C2-C12, more preferably C2-C10) olefins (the Mn of the(co)polymer is preferably 10,000 to 150,000, more preferably 15,000 to70,000; and the melt flow rate (hereinafter abbreviated as MFR; unit:g/10 min) is preferably 0.5 to 150, more preferably 1 to 100) in which apropylene-derived structure unit accounts for 30 mol % or more of thepolyolefin. The MFR herein is a numerical value representing the meltviscosity of the resin. A larger MFR indicates a lower melt viscosity.The MFR is measured according to the method specified in JIS K7210-1(2014). In the case of polypropylene, the MFR is measured at 230° C.with a load of 2.16 kgf.

Examples of the C2-C30 olefins include C2-C30 α-olefins and C4-C30dienes.

Examples of the C2-C30 α-olefins include ethylene, propylene, 1-butene,4-methyl-1-pentene, 1-pentene, 1-octene, 1-decene, 1-dodecene,1-icosene, and 1-tetracosene.

Examples of the C4-C30 dienes include butadiene, isoprene,cyclopentadiene, and 1,11-dodecadiene.

The C2-C30 olefin is preferably a C2-C12 α-olefin, butadiene, isoprene,or a mixture of these, more preferably a C2-C10 α-olefin, butadiene, ora mixture of these, particularly preferably ethylene, propylene (whichare C2-C3 α-olefins), or a mixture of these in terms of molecular weightcontrol.

<Polyolefin (a22) Having a Reactive Group at One End>

Examples of the polyolefin (a22) having a reactive group at one endinclude a polyolefin (a22-1) having a carboxy group or a carboxylic acidanhydride group at one end of the polymer, a polyolefin (a22-2) having ahydroxy group at one end of the polymer, a polyolefin (a2-3) having anamino group at one end of the polymer, a polyolefin (a22-4) having anisocyanate group at one end of the polymer, and a polyolefin (a22-5)having both a carboxy group and a hydroxy group at one end of thepolymer.

Of these, the polyolefin (a22-1) having a carboxy group or a carboxylicacid anhydride group at one end of the polymer is preferred in terms ofease of modification and heat resistance during molding.

The “one end” refers to either end in the main chain of the polymer.

The polyolefin (a22) having a reactive group at one end can be obtainedby, for example, introducing a carboxy group, a carboxylic acidanhydride group, a hydroxy group, an amino group, or an isocyanate groupinto a polyolefin (a22-0) mainly containing a polyolefin in which oneend is modifiable.

The “mainly containing” herein means that the weight of the polyolefinin which one end is modifiable accounts for 50 wt % or more of theweight of the whole polyolefin.

However, even when the weight of the polyolefin in which one end ismodifiable accounts for less than 50 wt % of the weight of the wholepolyolefin, if the total weight of the polyolefin in which one end ismodifiable and a polyolefin in which each end is modifiable describedabove accounts for 50 wt % or more of the weight of the wholepolyolefin, and the weight of the polyolefin in which one end ismodifiable is greater than the weight of the polyolefin in which eachend is modifiable, such a polyolefin is considered to be the polyolefin(a22-0) mainly containing a polyolefin in which one end is modifiable.

The polyolefin (a22-0) mainly containing a polyolefin in which one endis modifiable can be obtained in the same manner as in the case of thepolyolefin (a21-0) mainly containing a polyolefin in which each end ismodifiable.

The polyolefin (a21-0) mainly containing a polyolefin in which each endis modifiable and the polyolefin (a22-0) mainly containing a polyolefinin which one end is modifiable are commonly obtained as a mixturecontaining these polyolefins. The mixture may be used as is, or eachpolyolefin may be separated by purification before use. The mixture ispreferred in terms of production cost or the like.

Hereinafter, a description is given on the polyolefins (a21-1) to(a21-4) each having a carboxy group, a carboxylic acid anhydride group,a hydroxy group, an amino group, or an isocyanate group at each end ofthe polyolefin (a21-0) mainly containing a polyolefin in which each endis modifiable. The polyolefins (a22-1) to (a22-4) having one of thesegroups at one end of the polyolefin (a22-0) mainly containing apolyolefin in which one end is modifiable can be obtained in the samemanner as in the case of the above-described polyolefins (a21-1) to(a21-4) by replacing the polyolefin (a21-0) mainly containing apolyolefin in which each end is modifiable with the polyolefin (a22-0)mainly containing a polyolefin in which one end is modifiable. Preferredexamples of the polyolefin (a21) having a reactive group at each end andpreferred examples of the polyolefin (a22) having a reactive group atone end are the same.

Examples of the polyolefin (a21-1) having a carboxy group or acarboxylic acid anhydride group at each end of the polymer include apolyolefin (a21-1-1) having a structure obtained by modifying the endsof the polyolefin (a21-0) mainly containing a polyolefin in which eachend is modifiable with an α,β-unsaturated carboxylic acid (anhydride), apolyolefin (a21-1-2) having a structure obtained by further modifyingthe polyolefin (a21-1-1) with a lactam or an aminocarboxylic acid, apolyolefin (a21-1-3) having a structure obtained by modifying thepolyolefin (a21-0) mainly containing a polyolefin in which each end ismodifiable by oxidation or hydroformylation, a polyolefin (a21-1-4)having a structure obtained by further modifying the polyolefin(a21-1-3) with a lactam or an aminocarboxylic acid, and mixtures of twoor more of these.

The “α,β-unsaturated carboxylic acid (anhydride)” refers to anα,β-unsaturated carboxylic acid or its anhydride.

The polyolefin (a21-1-1) can be obtained by modifying the polyolefin(a21-0) mainly containing a polyolefin in which each end is modifiablewith an α,β-unsaturated carboxylic acid (anhydride).

Examples of the α,β-unsaturated carboxylic acid (anhydride) usable formodification include monocarboxylic acids, dicarboxylic acids, andanhydrides of these. Specific examples include (meth)acrylic acid,maleic acid (or its anhydride), fumaric acid, itaconic acid (or itsanhydride), and citraconic acid (or its anhydride).

Of these, an anhydride of a mono- or dicarboxylic acid and adicarboxylic acid are preferred, maleic acid (or its anhydride) andfumaric acid are more preferred, and maleic acid (or its anhydride) isparticularly preferred in terms of ease of modification.

The “(meth)acrylic acid” refers to acrylic acid or methacrylic acid.

The polyolefin (a21-1-2) can be obtained by further modifying thepolyolefin (a21-1-1) with the lactam or the aminocarboxylic acid.

The polyolefin (a21-1-3) can be obtained by introducing a carboxy groupinto the polyolefin (a21-0) mainly containing a polyolefin in which eachend is modifiable through oxidation with oxygen and/or ozone (oxidationmethod) or through hydroformylation (oxo method). Introduction of acarboxy group by the oxidation method can be carried out by a knownmethod such as the method described in U.S. Pat. No. 3,692,877.Introduction of a carboxy group by hydroformylation can be carried outby various methods including known methods such as the method describedin Macromolecules, VOL. 31, p. 5943.

The polyolefin (a21-1-4) can be obtained by further modifying thepolyolefin (a21-1-3) with a lactam or an aminocarboxylic acid.

The polyolefin (a21-1) having a carboxy group or a carboxylic acidanhydride group at each end of the polymer has an acid value ofpreferably 4 to 100 mgKOH/g, more preferably 4 to 50 mgKOH/g,particularly preferably 5 to 30 mgKOH/g in terms of reactivity with thehydrophilic polymer (b).

Examples of the polyolefin (a21-2) having a hydroxy group at each end ofthe polymer include polyolefins each having a hydroxy group obtained bymodifying the polyolefin (a21-1) having a carboxy group or a carboxylicacid anhydride group at each end of the polymer with an amine having ahydroxy group, and mixtures of two or more of these.

Examples of the amine having a hydroxy group usable for modificationinclude C2-C10 amines having a hydroxy group. Specific examples include2-aminoethanol, 3-aminopropanol, 1-amino-2-propanol, 4-aminobutanol,5-aminopentanol, 6-aminohexanol, and3-aminomethyl-3,5,5-trimethylcyclohexanol.

The polyolefin (a21-2) having a hydroxy group at each end of the polymerhas a hydroxy value of preferably 4 to 100 mgKOH/g, more preferably 4 to50 mgKOH/g, particularly preferably 5 to 30 mgKOH/g in terms ofreactivity with the hydrophilic polymer (b).

Examples of the polyolefin (a21-3) having an amino group at each end ofthe polymer include polyolefins each having an amino group obtained bymodifying the polyolefin (a21-1) with a diamine, and mixtures of two ormore of these.

Examples of the diamine include C2-C12 diamines. Specific examplesinclude ethylenediamine, hexamethylenediamine, heptamethylenediamine,octamethylenediamine, and decamethylenediamine.

Of these, C2-C8 diamines (e.g., ethylenediamine, hexamethylenediamine,heptamethylenediamine, and octamethylenediamine) are preferred,ethylenediamine and hexamethylenediamine are more preferred, andethylenediamine is particularly preferred in terms of ease ofmodification.

The polyolefin (a21-3) having an amino group at each end of the polymerhas an amine value of preferably 4 to 100 mgKOH/g, more preferably 4 to50 mgKOH/g, particularly preferably 5 to 30 mgKOH/g in terms ofreactivity with the hydrophilic polymer (b).

Examples of the polyolefin (a21-4) having an isocyanate group at eachend of the polymer include polyolefins each having an isocyanate groupobtained by modifying the polyolefin (a21-2) with a polyisocyanate (withat least two isocyanate groups), and mixtures of two or more of these.

Examples of the polyisocyanate include aromatic polyisocyanates havingthe number of carbon atoms (the carbon atoms in the isocyanate group areexcluded; the same shall apply hereinafter) of 6 to 20, C2-C18 aliphaticpolyisocyanates, C4-C15 alicyclic polyisocyanates, C8-C15 aromaticaliphatic polyisocyanates, modified products of these polyisocyanates,and mixtures of two or more of these.

Examples of the polyolefin (a22-5) having both a carboxy group and ahydroxy group at one end of the polymer include a polyolefin (a22-5-1)having a structure obtained by firstly modifying one end of thepolyolefin (a22-0) mainly containing a polyolefin in which one end ismodifiable with an α,β-unsaturated carboxylic acid anhydride, andsecondly modifying the resultant polyolefin with a diol amine.

Examples of the diol amine used for the second modification includediethanolamine.

The polyolefin (a21) having a reactive group at each end and thepolyolefin (a22) having a reactive group at one end each have a Mn ofpreferably 1,000 to 25,000, more preferably 1,500 to 12,000,particularly preferably 2,000 to 7,000 in terms of antistatic property.

<Polyester (a3)>

The polyester (a3) in the present invention is, for example, a polymercontaining a diol (a31) and a dicarboxylic acid (a32) as constituentmonomers.

Examples of the diol (a31) include an aliphatic diol (a311) and anaromatic group-containing diol (a312).

Examples of the dicarboxylic acid (a32) include an aliphaticdicarboxylic acid (a321) and an aromatic dicarboxylic acid (a322).

The diol (a31) may be one of the above diols or a mixture of two or moreof these.

Examples of the aliphatic diol (a311) include 1,2-ethanediol (ethyleneglycol), 1,2-propanediol (propylene glycol), 1,3-propanediol,1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol,1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentylglycol), 2,2-diethyl-1,3-propanediol (3,3-dimethylolpentane),2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolpentane),3-methyl-1,5-pentanediol, 1,6-hexanediol,2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol,2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol,1,12-octadecanediol, 1,4-cyclohexanedimethanol, hydrogenated bisphenolA, 1,2-, 1,3-, or 1,4-cyclohexanediol, cyclododecanediol, dimer diol,hydrogenated dimer diol, diethylene glycol, dipropylene glycol, andtriethylene glycol.

Examples of the aromatic group-containing diol (a312) include bisphenolA, 1,2-hydroxybenzene, 1,3-hydroxybenzene, 1,4-hydroxybenzene, and1,4-benzenedimethanol.

Examples of the aliphatic dicarboxylic acid (a321) include C2-C20(preferably C4-C16) aliphatic dicarboxylic acids, oxalic acid, malonicacid, succinic acid, glutaric acid, adipic acid, pimelic acid, subericacid, azelaic acid, sebacic acid, 1,10-decandicarboxylic acid,1,4-cyclohexanedicarboxylic acid, dimer acid, maleic acid, and fumaricacid.

The aliphatic dicarboxylic acid (a321) may be an alkyl ester or a halideof any of the above acids.

Examples of the aromatic dicarboxylic acid (a322) include C8-C20aromatic dicarboxylic acids, terephthalic acid, isophthalic acid,phthalic acid, phenylmalonic acid, homophthalic acid, phenylsuccinicacid, β-phenylglutaric acid, α-phenyladipic acid, β-phenyladipic acid,biphenyl-2,2′-dicarboxylic acid, biphenyl-4,4′-dicarboxylic acid, andnaphthalenedicarboxylic acid.

The aromatic dicarboxylic acid (a322) may be an alkyl ester or a halideof any of the above acids.

The polyester (a3) has a Mn of preferably 800 to 8,000, more preferably1,000 to 6,000, particularly preferably 2,000 to 4,000 in terms ofantistatic property and moldability.

<Hydrophilic Polymer (b)>

Examples of the hydrophilic polymer (b) in the present invention includehydrophilic polymers described in JP 3488163 B. Specific examplesinclude a polyether (b1) and a polyether-containing hydrophilic polymer(b2). The polyether (b1) is preferred in terms of antistatic propertyand resin properties.

Preferably, the hydrophilic polymer (b) in the present invention is apolymer having a volume specific resistance of 1×10¹¹ Ω·cm or less.

Examples of the polyether (b1) include a polyetherdiol (b1-1), apolyetherdiamine (b1-2), and modified products (b1-3) of these.

Examples of the polyetherdiol (b1-1) include those obtained by additionreaction of an alkylene oxide (hereinafter abbreviated as AO) to a diol(b0). Specific examples include those represented by the formula (1):H—(OR¹)_(a)—O-E¹-O—(R²O)_(b)—H  (1).

E¹ in the formula (1) is a residue obtained by removing all hydroxygroups from the diol (b0).

R¹ and R² in the formula (1) are each independently a C2-C12 alkylenegroup, a styrene group, or a chloromethyl group. Of these, a C2-C4alkylene group is preferred. Examples of the C2-C4 alkylene groupinclude an ethylene group, a 1,2- or 1,3-propylene group, and a 1,2-,1,3-, 1,4-, or 2,3-butylene group.

The letters “a” and “b” in the formula (1) are the average numbers ofmoles of (OR¹) and (R²O) added, respectively, and are each independently1 to 300, preferably 2 to 250, more preferably 10 to 100.

When “a” and “b” in the formula (1) are each 2 or greater, R¹ and R² maybe the same as or different from each other, and (OR¹)_(a) and (R²O)_(b)moieties may be bonded in a random form or a block form.

Examples of the diol (b0) include C2-C12 aliphatic dihydric alcohols,C5-C12 alicyclic dihydric alcohols, C6-C18 aromatic dihydric alcohols,and tertiary amino-containing diols.

Examples of the C2-C12 aliphatic dihydric alcohols include ethyleneglycol (hereinafter abbreviated as EG), 1,2-propylene glycol,1,4-butanediol, 1,6-hexanediol, neopentyl glycol, and 1,12-dodecanediol.

Examples of the C5-C12 alicyclic dihydric alcohols include1,4-di(hydroxymethyl)cyclohexane and 1,5-di(hydroxymethyl)cycloheptane.

Examples of the C6-C18 aromatic dihydric alcohols include monocyclicaromatic dihydric alcohols (xylylenediol, hydroquinone, catechol,resorcin, and urushiol) and polycyclic aromatic dihydric alcohols (e.g.,bisphenol A, bisphenol F, bisphenol S,4,4′-dihydroxydiphenyl-2,2-butane, dihydroxybiphenyl,dihydroxynaphthalene, and binaphthol).

Examples of the tertiary amino-containing diols includebishydroxyalkylates of C1-C12 aliphatic or alicyclic primary amines(e.g., methylamine, ethylamine, cyclopropylamine, 1-propylamine,2-propylamine, pentylamine, isopentylamine, cyclopentylamine,hexylamine, cyclohexylamine, heptylamine, nonylamine, decylamine,undecylamine, and dodecylamine), and bishydroxyalkylates of C6-C12aromatic primary amines (e.g., aniline and benzylamine).

Of these, the diol (b0) is preferably a C2-C12 aliphatic dihydricalcohol or a C6-C18 aromatic dihydric alcohol, more preferably EG orbisphenol A in terms of reactivity with a bishydroxyalkylate.

The polyetherdiol (b1-1) can be produced by addition reaction of an AOto the diol (b0).

The AO is a C2-C4 AO (ethylene oxide (hereinafter abbreviated as EO),1,2- or 1,3-propylene oxide, 1,2-, 1,3-, 1,4-, or 2,3-butylene oxide, ora combination of two or more of these). If necessary, an additional AO(e.g., C5-C12 α-olefin oxide, styrene oxide, or epihalohydrin (e.g.,epichlorohydrin)) may be also used in a small portion (30 wt % or lessbased on the total weight of AOs).

The bonding form when two or more AOs are used in combination may beeither a random form or a block form. The AO is preferably an EO aloneor a combination of an EO and an additional AO.

The addition reaction of an AO can be carried out by a known method, forexample, at a temperature of 100° C. to 200° C. in the presence of analkaline catalyst.

The (OR¹)_(a) and (R²O)_(b) content based on the weight of thepolyetherdiol (b1-1) represented by the formula (1) is preferably 5 to99.8 wt %, more preferably 8 to 99.6 wt %, particularly preferably 10 to98 wt %.

The oxyethylene group content based on the weight of (OR¹)_(a) and(R²O)_(b) in the formula (1) is preferably 5 to 100 wt %, morepreferably 10 to 100 wt %, particularly preferably 50 to 100 wt %, mostpreferably 60 to 100 wt %.

The polyetherdiol (b1-1) is preferably a bisphenol A EO adduct orpolyethylene glycol.

Examples of the polyetherdiamine (b1-2) include those represented by theformula (2):H₂N—R³—(OR⁴)_(c)—O-E²-O—(R⁵O)_(d)—R⁶—NH₂  (2).

E² in the formula (2) is a residue obtained by removing all hydroxygroups from the diol (b0).

Examples of the diol (b0) and preferred scope thereof are the same asthose mentioned above for the polyetherdiol (b1-1).

R³, R⁴, R⁵, and R⁶ in the formula (2) are each independently a C2-C4alkylene group, a C5-C12 alkylene group, a styrene group, or achloromethyl group. Examples of the C2-C4 alkylene groups include thosementioned as examples of R² and R² in the formula (1).

The letters “c” and “d” in the formula (2) are the average numbers ofmoles of (OR⁴) and (R⁵O) added, respectively, and are each independently1 to 300, preferably 2 to 250, more preferably 10 to 100.

When “c” and “d” in the formula (2) are each 2 or greater, R⁴ and R⁵ maybe the same as or different from each other, and (OR⁴)_(c) and (R⁵O)_(d)moieties may be bonded in a random form or a block form.

The polyetherdiamine (b1-2) can be obtained by converting all hydroxygroups of the polyetherdiol (b1-1) to alkyl amino groups. For example,the polyetherdiamine (b1-2) can be produced by reacting thepolyetherdiol (b1-1) with acrylonitrile, and hydrogenating the resultingcyanoethylate.

Examples of the modified products (b1-3) include an aminocarboxylic acidmodified product (terminated with an amino group) of the polyetherdiol(b1-1) or the polyetherdiamine (b1-2), an isocyanate modified product(terminated with an isocyanate group) of the polyetherdiol (b1-1) or thepolyetherdiamine (b1-2), and an epoxy modified product (terminated withan epoxy group) of the polyetherdiol (b1-1) or the polyetherdiamine(b1-2).

The aminocarboxylic acid modified product can be obtained by reactingthe polyetherdiol (b1-1) or the polyetherdiamine (b1-2) with anaminocarboxylic acid or a lactam.

The isocyanate modified product can be obtained by reacting thepolyetherdiol (b1-1) or the polyetherdiamine (b1-2) with apolyisocyanate, or by reacting the polyetherdiamine (b1-2) withphosgene.

The epoxy modified product can be obtained by reacting the polyetherdiol(b1-1) or the polyetherdiamine (b1-2) with a diepoxide (an epoxy resinsuch as diglycidyl ether, diglycidyl ester, or alicyclic diepoxide;epoxy equivalent: 85 to 600), or by reacting the polyetherdiol (b1-1)with epihalohydrin (e.g., epichlorohydrin).

The hydrophilic polymer (b) has a Mn of preferably 150 to 20,000, morepreferably 300 to 18,000, particularly preferably 1,000 to 15,000, mostpreferably 1,200 to 8,000 in terms of heat resistance and reactivitywith the hydrophobic polymer (a).

<Block Polymer (A)>

The block polymer (A) in the antistatic agent for thermoplastic resins(Z) of the present invention contains a block of the hydrophobic polymer(a) and a block of the hydrophilic polymer (b) as structure units. Theblock polymer (A) may contain one or more hydrophobic polymers (a) andone or more hydrophilic polymers (b).

The weight ratio of a block of the hydrophobic polymer (a) to a block ofthe hydrophilic polymer (b) constituting the block polymer (A) (weightof a block of the hydrophobic polymer (a)/weight of a block of thehydrophilic polymer (b)) is preferably 10/90 to 80/20, more preferably20/80 to 75/25 in terms of antistatic property and water resistance.

Examples of the structure in which a block of the hydrophobic polymer(a) and a block of the hydrophilic polymer (b) constituting the blockpolymer (A) are bonded include a (a)-(b) structure, a (a)-(b)-(a)structure, a (b)-(a)-(b) structure, and a [(a)-(b)]n structure (nindicates the average repeating number).

Preferably, the structure of the block polymer (A) is the [(a)-(b)]nstructure in which the hydrophobic polymer (a) and the hydrophilicpolymer (b) are alternately repeatedly bonded in terms of conductivity.

The “n” in the [(a)-(b)]n structure is preferably 2 to 50, morepreferably 2.3 to 30, particularly preferably 2.7 to 20, most preferably3 to 10 in terms of antistatic property and mechanical strength(mechanical properties). The “n” can be determined from the Mn of theblock polymer (A) and ¹H-NMR analysis.

The block polymer (A) has a Mn of preferably 2,000 to 100,000, morepreferably 5,000 to 60,000, particularly preferably 10,000 to 40,000 interms of mechanical strength (mechanical properties) and antistaticproperty of the resulting molded article (described later).

In the case where the block polymer (A) has a structure in which a blockof the hydrophobic polymer (a) and a block of the hydrophilic polymer(b) are bonded via an ester bond, an amide bond, an ether bond, or animide bond, such a block polymer (A) can be produced by the followingmethod.

Of these bonds, an ester bond and an amide bond are preferred in termsof industrial applications.

The hydrophobic polymer (a) and the hydrophilic polymer (b) are chargedinto a reaction vessel, and the mixture is reacted with stirring at areaction temperature of 100° C. to 250° C. at a pressure of 0.003 to 0.1MPa for 1 to 50 hours while water generated in amidation,esterification, etherification, or imidization (hereinafter, abbreviatedas generated water) is removed from the reaction system. The hydrophobicpolymer (a) and the hydrophilic polymer (b) for use in the reaction aremixed at a weight ratio (weight of the hydrophobic polymer (a)/weight ofthe hydrophilic polymer (b)) of 10/90 to 80/20, preferably 20/80 to75/25 in terms of antistatic property and water resistance.

In the case of esterification, use of 0.05 to 0.5 wt % of a catalystbased on the total weight of the hydrophobic polymer (a) and thehydrophilic polymer (b) is preferred in order to promote the reaction.Examples of the catalyst include inorganic acids (e.g., sulfuric acidand hydrochloric acid), organic sulfonic acids (e.g., methanesulfonicacid, p-toluenesulfonic acid, xylenesulfonic acid, andnaphthalenesulfonic acid), antimony catalysts (e.g., antimony trioxide),tin catalysts (e.g., monobutyltin oxide and dibutyltin oxide), titaniumcatalysts (e.g., tetrabutyl titanate, bistriethanolamine titanate, andtitanium potassium oxalate), zirconium catalysts (e.g., tetrabutylzirconate and zirconium oxyacetate), and zinc catalysts (e.g., zincacetate). In the case of using a catalyst, after the esterification, thecatalyst may be neutralized if necessary, and removed by treatment withan absorber for purification.

The generated water is removed from the reaction system, for example, byany of the following methods:

(1) a method of using an organic solvent not compatible with water(e.g., toluene, xylene, or cyclohexane) and azeotropically boiling theorganic solvent and the generated water under reflux, thereby removingthe generated water alone from the reaction system;

(2) a method of blowing a carrier gas (e.g., air, nitrogen, helium,argon, or carbon dioxide) into the reaction system, thereby removing thegenerated water from the reaction system together with the carrier gas;and

(3) a method of reducing the pressure inside the reaction system,thereby removing the generated water from the reaction system.

<C6-C18 Branched Alkylbenzenesulfonate (S)>

The C6-C18 branched alkylbenzenesulfonate (S) (branchedalkylbenzenesulfonate whose branched alkyl group has 6 to 18 carbonatoms), hereinafter also referred to as the salt (S), in the presentinvention is made of an anion of a branched alkylbenzenesulfonic acidand a cation.

Herein, the branched alkylbenzenesulfonic acid refers to abenzenesulfonic acid substituted by an alkyl group having a branchedstructure. A straight-chain alkylbenzenesulfonic acid refers to abenzenesulfonic acid substituted by an alkyl group not having a branchedstructure. Herein, the branched alkyl includes an alkyl group includingtwo or more methyl groups. In other words, it refers to an alkyl groupsubstituted by one or more alkyl groups. For example, a 1-ethylbutylgroup [CH₃(CH₂)₂(CH₃CH₂)CH—] is a butyl group substituted by an ethylgroup (CH₃CH₂—) in which methyl groups are present at the end of thebutyl group and in the ethyl group, so that it is a branched alkylincluding a total of two methyl groups. The straight-chain alkyl otherthan the branched type is an alkyl group including one methyl group.

The C6-C18 branched alkylbenzenesulfonate (S) can improve the continuousmoldability (demoldability) during molding.

The number of carbon atoms of the branched alkyl group of the C6-C18branched alkylbenzenesulfonic acid anion is preferably 8 to 16, morepreferably 10 to 14. The anion is particularly preferably an anion of abranched dodecylbenzenesulfonic acid.

Examples of cations forming the salt (S) include alkali metal (e.g.,lithium, sodium, or potassium) cations and imidazolium cations.

Examples of the imidazolium cations include C5-C15 imidazolium cations,such as 1,3-dimethylimidazolium cation, 1,3-diethylimidazolium cation,1-ethyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation,1,2,3-trimethylimidazolium cation, 1,2,3,4-tetramethylimidazoliumcation, 1-ethyl-2,3-dimethylimidazolium cation,1,3-dimethyl-2-ethylimidazolium cation, 1,2-dimethyl-3-ethyl-imidazoliumcation, 1,2,3-triethylimidazolium cation, 1,2,3,4-tetraethylimidazoliumcation, 1,3-dimethyl-2-phenylimidazolium cation,1,3-dimethyl-2-benzylimidazolium cation,1-benzyl-2,3-dimethyl-imidazolium cation,4-cyano-1,2,3-trimethylimidazolium cation,3-cyanomethyl-1,2-dimethylimidazolium cation,2-cyanomethyl-1,3-dimethyl-imidazolium cation,4-acetyl-1,2,3-trimethylimidazolium cation,3-acetylmethyl-1,2-dimethylimidazolium cation,4-methylcarboxymethyl-1,2,3-trimethylimidazolium cation,3-methylcarboxymethyl-1,2-dimethylimidazolium cation,4-methoxy-1,2,3-trimethylimidazolium cation,3-methoxymethyl-1,2-dimethylimidazolium cation,4-formyl-1,2,3-trimethylimidazolium cation,3-formylmethyl-1,2-dimethylimidazolium cation,3-hydroxyethyl-1,2-dimethylimidazolium cation,4-hydroxymethyl-1,2,3-trimethylimidazolium cation, and2-hydroxyethyl-1,3-dimethylimidazolium cation.

Of these cations forming the salt (S), a sodium cation and animidazolium cation are preferred, a sodium cation and a1-alkyl-3-alkylimidazolium cation which has C1-C3 alkyl groups at 1- and3-positions are more preferred, and a 1-ethyl-3-methylimidazolium cationis particularly preferred in terms of antistatic property.

<Antistatic Agent for Thermoplastic Resins (Z)>

The antistatic agent for thermoplastic resins (Z) of the presentinvention contains the block polymer (A) and the salt (S).

The weight ratio of the block polymer (A) to the salt (S) (weight of theblock polymer (A)/weight of the salt (S)) is preferably 90/10 to 99/1,more preferably 92/8 to 98/2, still more preferably 93/7 to 97/3 interms of mechanical strength and antistatic property.

The antistatic agent for thermoplastic resins (Z) can be produced, forexample, by the following method (1) or (2):

-   (1) mixing the block polymer (A) and the salt (S); or-   (2) reacting a polymer of a hydrophobic block (a) and a polymer of a    hydrophilic block (b) by a known method to obtain the block    polymer (A) while adding with the salt (S) before or in the middle    of the reaction.    <Antistatic Resin Composition (Y)>

The antistatic resin composition (Y) of the present invention containsthe antistatic agent (Z) and a thermoplastic resin (E) (describedlater).

The weight ratio of the antistatic agent (Z) to the thermoplastic resin(E) (weight of the antistatic agent (Z)/weight of the thermoplasticresin (E)) is preferably 3/97 to 20/80, more preferably 5/95 to 15/85 interms of antistatic property and mechanical strength (mechanicalproperties).

Examples of the thermoplastic resin (E) include a polyphenylene etherresin (E1);

vinyl resins, such as a polyolefin resin (E2) (e.g., polypropylene,polyethylene, ethylene-vinyl acetate copolymer resin (EVA), andethylene-ethylacrylate copolymer resin), a poly(meth) acrylic resin (E3)(e.g., polymethylmethacrylate), a polystyrene resin (E4) (a vinylgroup-containing aromatic hydrocarbon alone, or a copolymer containing avinyl group-containing aromatic hydrocarbon and at least one selectedfrom the group consisting of a (meth)acrylic acid ester,(meth)acrylonitrile, and butadiene as structure units, such aspolystyrene (PS), a styrene/acrylonitrile copolymer (AN resin), anacrylonitrile/butadiene/styrene copolymer (ABS resin), a methylmethacrylate/butadiene/styrene copolymer (MBS resin), and astyrene/methyl methacrylate copolymer (MS resin)); a polyester resin(E5) (e.g., polyethylene terephthalate, polybutylene terephthalate,polycyclohexanedimethylene terephthalate, polybutylene adipate, andpolyethylene adipate); a polyamide resin (E6) (e.g., nylon 66, nylon 69,nylon 612, nylon 6, nylon 11, nylon 12, nylon 46, nylon 6/66, and nylon6/12); a polycarbonate resin (E7) (e.g., polycarbonate andpolycarbonate/ABS alloy resin); a polyacetal resin (E8); and mixtures oftwo or more of these.

Of these, the polyolefin resin (E2), the polystyrene resin (E4), and thepolycarbonate resin (E7) are preferred, and the polystyrene resin (E4)is more preferred in terms of mechanical strength (mechanicalproperties) and antistatic property of the resulting molded article(described later).

The antistatic resin composition (Y) of the present invention mayfurther contain a known additive for resins (G) if necessary, within arange that does not impair the effects of the present invention.

Examples of the additive for resins (G) include compatibilizers (e.g.,carboxylic acid modified polypropylene), flame retardants (e.g.,guanamine), pigments (e.g., titanium oxide), dyes (e.g., azo dye),nucleating agents (e.g., talc), lubricants (e.g., cabana wax),plasticizers (e.g., dioctyl phthalate), antioxidants (e.g., triphenylphosphite), and ultraviolet absorbers (e.g.,2-(2′-hydroxy-5′-methylphenyl)benzotriazole).

The amount of the additive for resins (G) varies depending on theapplication. Yet, for example, it is 45 wt % or less based on the totalweight of the antistatic agent (Z) and the thermoplastic resin (E). Itis preferably 0.01 to 30 wt %, more preferably 0.1 to 10 wt % in termsof effect by the addition.

The antistatic resin composition (Y) of the present invention isobtained by melt-mixing the antistatic agent (Z), the thermoplasticresin (E), and, optionally, the additive for resins (G).

The melt-mixing method is generally a method including mixing pellet orpowered components in a suitable mixer, for example, Henschel mixer, andthen pelletizing by melt-mixing with an extruder.

The addition order of the components in melt-mixing is not limited, andmethods may include, for example:

(1) melt-mixing the antistatic agent (Z), the thermoplastic resin (E),and, optionally, the additive for resins (G) together; and

(2) melt-mixing the antistatic agent (Z) and a portion of thethermoplastic resin (E) in advance to prepare a resin composition(master batch resin composition) with a high content of the antistaticagent (Z), and then melt-mixing the remaining thermoplastic resin (E)and, optionally, the additive for resins (G).

<Molded Article>

The molded article of the present invention is obtained by molding theantistatic resin composition (Y). Examples of the molding method includeinjection molding, compression molding, calendaring molding, slushmolding, rotational molding, extrusion molding, blow molding, foammolding, film molding (e.g. casting method, tenter method, and inflationmethod). The antistatic resin composition (Y) can be molded by anymethod suitable for the purpose.

The antistatic agent for thermoplastic resins (Z) of the presentinvention imparts excellent antistatic property to molded articlescontaining the thermoplastic resin (E). An antistatic resin compositioncontaining the antistatic agent for thermoplastic resins (Z) of thepresent invention has excellent continuous moldability (demoldability)during molding, and the resulting molded articles have excellentmechanical strength (mechanical properties).

Thus, the antistatic resin composition is widely usable as a material ofhousing products (home appliances, office automation (OA) machines,gaming machines, and office appliances), plastic container materials(trays for cleanrooms (e.g., IC trays), and other containers), variousbuffer materials, covering materials (e.g. packaging films andprotective films)), sheets of flooring material, artificial grass, mats,substrates of a tape (for a semiconductor fabrication process or thelike), and various molded articles (e.g., automobile parts), which aremolded by various molding methods (injection molding, compressionmolding, calendaring molding, slush molding, rotational molding,extrusion molding, blow molding, foam molding, and film molding (e.g.,casting method, tenter method, and inflation method)). Thus, theantistatic resin composition is very useful.

EXAMPLES

The present invention is described below with reference to the examplesand comparative examples, but the present invention is not limitedthereto. Parts in the examples represent weight parts, unless otherwisespecified.

Production Example 1

Production of Polyamide (a-1)

A stainless-steel pressure-resistant reaction vessel equipped with astirrer, a thermometer, a heating and cooling device, a nitrogen inlettube, and a decompression device was charged with c-caprolactam (79.4parts), terephthalic acid (11.5 parts), an antioxidant (“Irganox 1010”available from BASF Japan Ltd.) (0.3 parts), and water (6 parts). Afterpurging with nitrogen, the mixture was hermetically heated to 220° C.with stirring, and stirred at the same temperature (pressure: 0.2 to 0.3MPa) for four hours, thus obtaining a polyamide (a-1) having a carboxygroup at each end.

The polyamide (a-1) had an acid value of 78 and a Mn of 1,400.

Production Example 2

Production of Polyolefin (a2-1-1α) Having a Carboxy Group at Each End

A pressure-resistant reaction vessel similar to the one used inProduction Example 1 was charged with a low-molecular-weightpolypropylene obtained by thermal degradation (obtained by thermaldegradation of polypropylene (MFR: 10 g/10 min) at 410±0.1° C. undernitrogen aeration (80 mL/min) for 16 minutes; Mn: 3,400; number ofdouble bonds per 1,000 carbon atoms: 7.0; average number of double bondsper molecule: 1.8; content of polyolefins in which each end ismodifiable: 90 wt %) (90 parts), maleic anhydride (10 parts), and xylene(30 parts), and these components were uniformly mixed. After purgingwith nitrogen, the mixture was hermetically heated to 200° C. withstirring to be melted, and reacted at the same temperature for 10 hours.

Then, excess maleic anhydride and xylene were distilled off underreduced pressure (0.013 MPa or less) at 200° C. over three hours, thusobtaining a polyolefin (a2-1-1α) (95 parts) having a carboxy group ateach end of the polymer.

The polyolefin (a2-1-1α) had an acid value of 27.5 and a Mn of 3,600.

Production Example 3

Production of Polyolefin (a2-1-2) Obtained by Further ModifyingPolyolefin (a2-1-1α)

A pressure-resistant reaction vessel similar to the one used inProduction Example 1 was charged with the polyolefin (a2-1-1α) (88parts) and 12-aminododecanoic acid (12 parts), and these components wereuniformly mixed. Under nitrogen gas atmosphere, the mixture was heatedto 200° C. with stirring, and reacted under reduced pressure (0.013 MPaor less) at the same temperature for three hours, thus obtaining apolyolefin (a2-1-2) (96 parts) obtained by further modifying thepolyolefin (a2-1-1α).

The polyolefin (a2-1-2) had an acid value of 24.8 and a Mn of 4,000.

Production Example 4

Production of Polyester (a-3)

A stainless-steel pressure-resistant reaction vessel equipped with astirrer, a thermometer, a heating and cooling device, a nitrogen inlettube, and a decompression device was charged with 1,10-decandicarboxylicacid (68.4 parts), 1,6-hexanediol (31.6 parts), and an antioxidant(“Irganox 1010” available from BASF Japan Ltd.) (0.3 parts). Undergradual heating from 160° C. to 210° C., the mixture was polymerizedunder normal pressure for four hours and then at 210° C. under reducedpressure for three hours, thus obtaining a polyester (a-3) having acarboxy group at each end.

The polyester (a-3) had an acid value of 37 and a Mn of 3,000.

Production Example 5

Production of Polyamide (a-1-2)

A pressure-resistant reaction vessel similar to the one used inProduction Example 1 was charged with ω-laurolactam (82.5 parts),terephthalic acid (16.3 parts), an antioxidant (“Irganox 1010” availablefrom BASF Japan Ltd.) (0.3 parts), and water (10 parts). After purgingwith nitrogen, the mixture was hermetically heated to 220° C. withstirring, and stirred at the same temperature (pressure: 0.2 to 0.3 MPa)for four hours, thus obtaining a polyamide (a-1-2) having a carboxygroup at each end.

The polyamide (a-1-2) had an acid value of 109 and a Mn of 1,000.

Production Example 6

Production of Modified Polyolefin (a2-1-3) Having a Hydroxy Group atEach End of the Polymer

A pressure-resistant reaction vessel similar to the one used inProduction Example 1 was charged with the polyolefin (a2-1-1α) (95parts) and 2-aminoethanol (5 parts). The mixture was melted at 180° C.under a nitrogen gas atmosphere, and reacted at 180° C. for two hours.Subsequently, excess 2-aminoethanol was distilled off under reducedpressure at 180° C. for two hours, thus obtaining a modified polyolefin(a2-1-3) having a hydroxy group at each end of the polymer. The modifiedpolyolefin (a2-1-3) had a hydroxy value of 26.0, an amine value of 0.01,and a Mn of 3,900.

Production Example 7

Production of Polyester (a-3-2)

A stainless-steel pressure-resistant reaction vessel equipped with astirrer, a thermometer, a heating and cooling device, a nitrogen inlettube, and a decompression device was charged with terephthalic acid(69.7 parts), 1,4-butanediol (30.3 parts), and an antioxidant (“Irganox1010” available from BASF Japan Ltd.) (0.3 parts). Under gradual heatingfrom 160° C. to 210° C., the mixture was polymerized under normalpressure for four hours and then at 210° C. under reduced pressure forthree hours, thus obtaining a polyester (a-3-2) having a carboxy groupat each end. The polyester (a-3-2) had an acid value of 107 and a Mn of1,000.

Production Example 8

Block Polymer (A-1)

A reaction vessel equipped with a stirrer, a thermometer, and a heatingand cooling device was charged with the polyamide (a-1) (223 parts) asthe hydrophobic polymer (a), an EO adduct (Mn: 1,800) (279 parts) ofbisphenol A as the hydrophilic polymer (b), and zirconium oxyacetate (7parts). The mixture was heated to 240° C. with stirring, and polymerizedunder reduced pressure (0.013 MPa or less) at the same temperature forsix hours, thus obtaining a block polymer (A-1).

The block polymer (A-1) had a Mn of 22,000 and a weight ratio (weight ofthe hydrophobic polymer (a)/weight of the hydrophilic polymer (b)) of44/56.

Production Example 9

Block Polymer (A-2)

A pressure-resistant reaction vessel similar to the one used inProduction Example 8 was charged with the polyolefin (a2-1-2) (60.1parts) as the hydrophobic polymer (a), a polyetherdiol (b1-1α) (PEG (Mn:3,000; volume specific resistance: 1×10⁷ (Ω·cm)) (39.9 parts) as thehydrophilic polymer (b), an antioxidant “Irganox 1010” (0.3 parts), andzirconyl acetate (0.5 parts). The mixture was heated to 220° C. withstirring, and polymerized under reduced pressure (0.013 MPa or less) atthe same temperature for three hours, thus obtaining a viscous blockpolymer (A-2).

The block polymer (A-2) had a Mn of 30,000 and a weight ratio (weight ofthe hydrophobic polymer (a)/weight of the hydrophilic polymer (b)) of60/40.

Production Example 10

Block Polymer (A-3)

A pressure-resistant reaction vessel similar to the one used inProduction Example 8 was charged with the polyester (a-3) (50 parts) asthe hydrophobic polymer (a), the polyetherdiol (b1-1α) (PEG (Mn: 3,000;volume specific resistance: 1×10⁷ Ω·cm)) (50 parts) as the hydrophilicpolymer (b), an antioxidant “Irganox 1010” (0.3 parts), and zirconylacetate (0.5 parts). The mixture was heated to 220° C. with stirring,and polymerized under reduced pressure (0.013 MPa or less) at the sametemperature for three hours, thus obtaining a viscous block polymer(A-3). The block polymer (A-3) had a Mn of 24,000 and a weight ratio(weight of the hydrophobic polymer (a)/weight of the hydrophilic polymer(b)) of 50/50.

Production Example 11

Block Polymer (A-4)

A reaction vessel equipped with a stirrer, a thermometer, and a heatingand cooling device was charged with the polyamide (a-1-2) (253 parts) asthe hydrophobic polymer (a), polyethylene glycol (Mn: 1,000) (253 parts)as the hydrophilic polymer (b), and zirconium oxyacetate (7 parts). Themixture was heated to 240° C. with stirring, and polymerized underreduced pressure (0.013 MPa or less) at the same temperature for sixhours, thus obtaining a block polymer (A-4).

The block polymer (A-4) had a Mn of 30,000 and a weight ratio (weight ofthe hydrophobic polymer (a)/weight of the hydrophilic polymer (b)) of50/50.

Production Example 12

Block Polymer (A-5)

A pressure-resistant reaction vessel similar to the one used inProduction Example 8 was charged with the modified polyolefin (a2-1-3)(59.0 parts) as the hydrophobic polymer (a), an EO adduct (Mn: 2,900)(41.0 parts) of bisphenol A as the hydrophilic polymer (b), dodecanediacid (6.0 parts), an antioxidant “Irganox 1010” (0.3 parts), andzirconium oxyacetate (0.5 parts). The mixture was heated to 220° C. withstirring, and polymerized under reduced pressure (0.013 MPa or less) atthe same temperature for three hours, thus obtaining a viscous blockpolymer (A-5). The block polymer (A-5) had a Mn of 25,000 and a weightratio (weight of the hydrophobic polymer (a)/weight of the hydrophilicpolymer (b)) of 59/41.

Production Example 13

Block Polymer (A-6)

A pressure-resistant reaction vessel similar to the one used inProduction Example 8 was charged with the polyester (a-3-2) (35.7 parts)as the hydrophobic polymer (a), an EO adduct (Mn: 1,800) (64.3 parts) ofbisphenol A as the hydrophilic polymer (b), an antioxidant “Irganox1010” (0.3 parts), and zirconium oxyacetate (0.5 parts). The mixture washeated to 220° C. with stirring, and polymerized under reduced pressure(0.013 MPa or less) at the same temperature for three hours, thusobtaining a viscous block polymer (A-6). The block polymer (A-6) had aMn of 28,000 and a weight ratio (weight of the hydrophobic polymer(a)/weight of the hydrophilic polymer (b)) of 36/64.

Example 1

A reaction vessel equipped with a stirrer, a thermometer, and a heatingand cooling device was charged with the block polymer (A-1) (97 parts)and a branched sodium dodecylbenzenesulfonate (S-1) (3 parts). Aftermixing and stirring at 220° C. for one hour, the mixture was taken outin the form of a strand onto a belt and pelletized, thus obtaining anantistatic agent (Z-1).

Examples 2 to 8 and Comparative Examples 1 to 4

In each of the examples and the comparative examples, the antistaticagent (Z) was obtained as in Example 1, except for following theformulation (by parts) shown in Table 1.

TABLE 1 Example Comparative Example 1 2 3 4 5 6 7 8 1 2 3 4 Antistaticagent (Z) Z-1 Z-2 Z-3 Z-4 Z-5 Z-6 Z-7 Z-8 Comparative ComparativeComparative Comparative Example Z-1 Example Z-2 Example Z-3 Example Z-4Formu- Block (A-1) 97 95 97 — — — — — 100 97 95 97 lation polymer (A-2)— — — 97 — — — — — — — — (parts (A-3) — — — — 97 — — — — — — — by (A-4)— — — — — 93 — — — — — — weight) (A-5) — — — — — — 95 — — — — — (A-6) —— — — — — — 95 — — — — Salt (S-1)  3  5 —  3  3 — — — — — — — (S-2) — — 3 — —  7  5  5 — — — — (Comparative — — — — — — — — —  3  5 — ExampleS-1) (Comparative — — — — — — — — — — —  3 Example S-2) <Materials used>(S-1): Branched sodium dodecylbenzenesulfonate (S-2): Branched1-ethyl-3-methylimidazolium dodecylbenzenesulfonate (Comparative ExampleS-1): Straight-chain sodium dodecylbenzenesulfonate (Comparative ExampleS-2): Straight-chain 1-ethyl-3-methylimidazolium dodecylbenzenesulfonate

Examples 9 to 16 and Comparative Examples 5 to 8

In each of the examples and the comparative examples, the antistaticagent (Z) and the thermoplastic resin (E) were blended following theformulation shown in Table 2 with a Henschel mixer for three minutes.Then, the mixture was melt-kneaded in a twin-screw extruder with a ventat 100 rpm with a retention time of three minutes at 230° C., thusobtaining the antistatic resin composition (Y).

Each of the resulting antistatic resin compositions (Y) was evaluatedaccording to <Evaluation method> described later. Table 2 shows theresults.

<Evaluation Method>

1. Demoldability (Continuous Moldability)

From each resin composition, a flat plate test piece (length 70 mm,width 70 mm, thickness 2 mm) was produced using an injection moldingmachine (product name “PS40E5ASE” available from Nissei PlasticIndustrial Co., Ltd.) at a cylinder temperature of 260° C., a moldtemperature of 80° C., and a molding cycle of 30 seconds. After 2000shots of injection molding, the demoldability of each test piece wasevaluated according to <Evaluation criteria> described below.

The demoldability was evaluated based on the following formula (1):Demoldability (%)=(D2000)×100/(D1)  (1)where (D1) is the resisting force (unit: N) required for demolding atthe first shot, and (D2000) is the resisting force required fordemolding at the 2000th shot.<Evaluation Criteria>

-   ◯◯: less than 110%-   ◯: 110% or more and less than 120%-   Δ: 120% or more and less than 130%-   x: 130% or more    2. Surface Specific Resistance (Unit: Ω)

From each resin composition, a flat plate test piece (length 100 mm,width 100 mm, thickness 2 mm) was produced using an injection moldingmachine (product name “PS40E5ASE” available from Nissei PlasticIndustrial Co., Ltd.) at a cylinder temperature of 260° C. and a moldtemperature of 80° C. Each flat plate test piece was measured using anultra megohmmeter “DSM-8103” (available from DKK-TOA co., Ltd.) under anatmospheric environment at 23° C. with a humidity of 40% RH.

3. Izod Impact Strength (Unit: J/m)

From each resin composition, a test piece was produced using aninjection molding machine (product name “PS40E5ASE” available fromNissei Plastic Industrial Co., Ltd.) at a cylinder temperature of 260°C. and a mold temperature of 80° C. Each test piece was measuredaccording to ASTM D256 Method A (with a notch, 3.2 mm thick).

TABLE 2 Example 9 10 11 12 13 14 15 Antistatic resin composition (Y) Y-1Y-2 Y-3 Y-4 Y-5 Y-6 Y-7 Formulation Antistatic Type Z-1 Z-2 Z-3 Z-4 Z-5Z-6 Z-7 agent (Z) Parts by 10 10 10 10 10  5  5 weight Thermo- Type E-1E-1 E-1 E-2 E-3 E-3 E-2 plastic Parts by 90 90 90 90 90  95 95 resin (E)weight Evaluation Demoldability ∘ ∘∘ ∘∘ ∘ ∘ ∘ ∘ results Surface specific2.0 × 10¹¹ 9.0 × 10¹⁰ 8.0 × 10¹⁰ 2.0 × 10¹¹ 2.0 × 10¹¹ 1.5 × 10¹¹ 1.5 ×10¹¹ resistance (Ω) Izod impact strength 155  150  160  80 155  160 80(J/m) Example Comparative Example 16 5 6 7 8 Antistatic resincomposition (Y) Y-8 Comparative Comparative Comparative ComparativeExample Y-1 Example Y-2 Example Y-3 Example Y-4 Formulation AntistaticType Z-8 Comparative Comparative Comparative Comparative agent (Z)Example Z-1 Example Z-2 Example Z-3 Example Z-4 Parts by 10 10 10 10 10weight Thermo- Type E-1 E-1 E-1 E-1 E-1 plastic Parts by 90 90 90 90 90resin (E) weight Evaluation Demoldability ∘∘ Δ Δ x Δ results Surfacespecific 8.5 × 10¹⁰ 2.0 × 10¹² 4.0 × 10¹¹ 2.5 × 10¹¹ 9.0 × 10¹⁰resistance (Ω) Izod impact strength 155  150  140  130  145  (J/m)Thermoplastic resin (E-1): ABS resin (product name “Cevian-V320”available from Daicel Miraizu Ltd.) (E-2): polypropylene resin (productname “SunAllomer PM771M” available from SunAllomer Co., Ltd.) (E-3):high impact PS resin (product name “HIPS 433” available from PS JapanCo., Ltd.)

The results in Tables 1 and 2 show that the antistatic agent forthermoplastic resins (Z) of the present invention has excellentantistatic property, imparts excellent mechanical strength to the moldedarticles, and also improves continuous moldability (demoldability)during molding, as compared to those of the comparative examples.

INDUSTRIAL APPLICABILITY

The antistatic agent for thermoplastic resins (Z) of the presentinvention imparts excellent antistatic property to molded articlescontaining a thermoplastic resin. The antistatic resin composition hasexcellent continuous moldability (demoldability) during molding, and theresulting molded articles have excellent mechanical strength.

Thus, the antistatic resin composition is widely usable as a material ofhousing products (home appliances, office automation (OA) machines,gaming machines, and office appliances), plastic container materials(trays for cleanrooms (e.g., IC trays), and other containers), variousbuffer materials, covering materials (e.g. packaging films andprotective films), sheets of flooring material, artificial grass, mats,substrates of a tape (for a semiconductor fabrication process or thelike), and various molded articles (e.g., automobile parts), which aremolded by various molding methods (injection molding, compressionmolding, calendaring molding, slush molding, rotational molding,extrusion molding, blow molding, foam molding, and film molding (e.g.,casting method, tenter method, and inflation method)). Thus, theantistatic resin composition is very useful.

The invention claimed is:
 1. An antistatic agent for thermoplasticresins (Z), comprising: a block polymer (A) having a block of ahydrophobic polymer (a) and a block of a hydrophilic polymer (b) asstructure units; and a C6-C18 branched alkylbenzenesulfonate (S),wherein a cation forming the C6-C18 branched alkylbenzenesulfonate (S)is an imidazolium cation or a sodium cation.
 2. The antistatic agent forthermoplastic resins (Z) according to claim 1, wherein the hydrophobicpolymer (a) comprises at least one selected from the group consisting ofa polyamide (a1), a polyolefin (a2), and a polyester (a3).
 3. Theantistatic agent for thermoplastic resins (Z) according to claim 1,wherein the hydrophilic polymer (b) is a polyether (b1).
 4. Theantistatic agent for thermoplastic resins (Z) according to claim 1,wherein the cation forming the C6-C18 branched alkylbenzenesulfonate (S)is an imidazolium cation.
 5. The antistatic agent for thermoplasticresins (Z) according to claim 1, wherein a weight ratio of the blockpolymer (A) to the C6-C18 branched alkylbenzenesulfonate (S) is 90:10 to99:1.
 6. An antistatic resin composition (Y), comprising: the antistaticagent for thermoplastic resins (Z) according to claim 1; and athermoplastic resin (E).
 7. The antistatic resin composition (Y)according to claim 6, wherein a weight ratio of the antistatic agent (Z)to the thermoplastic resin (E) is 3:97 to 20:80.
 8. A molded article,which is a molded article of the antistatic resin composition (Y)according to claim 6.